I think ive caught a power cable to my interior light as it very rarely works so i was wondering how hard they to take apart??

You mean the courtesy light on the roof? Very easy to get that out. Slide / pull the transparent plastic bit off (this is how you change those bulbs. Took me a while to figure that out!). Then under there you'll see two screws. Undo those and from what I remember it should just basically drop out. There's also some sort of magical black box hidden up there. I think it's something to do with the alarm system? Mine had worked itself loose and was rattling about.

I think ive caught a power cable to my interior light as it very rarely works so i was wondering how hard they to take apart??

It may be a faulty bulb ,where the filament has a break,in which the filament becomes open circuit when hot.

In addition to what has been said already, when you get to the bit with the screws, there are two tab things which need a screwdriver or simular pushed inside of to realise.